This invention relates to a clamping device which can be used in motor vehicle production lines and can travel in the direction of the production line. More particularly, this invention relates to a clamping device for rough car bodies traveling in the production line direction on a transport apparatus, which has side members on both sides of the production line, and crossbeams reaching over the rough car body and clamping elements for clamping the rough body, and in which the crossbeams are to be coupled together in the working position by a latch to form a single component clamping the rough car body. The invention furthermore relates to a production line having such a clamping device.
This application claims the priority of German application number 199 07 015.6, filed Feb. 18, 1999, the disclosure of which is expressly incorporated by reference herein.
A clamping device of this type is the subject of DE 195 33 389 A1. This publication also describes a production line with such a clamping device. In the known clamping device a base frame which can travel as a whole is provided, on which the side members are disposed. The transport apparatus for the rough bodies is disposed for travel on the base frame. Overall, the clamping device has two base frames disposed one behind the other with side members which bear variously configured clamps, so that one or the other clamping device can be used optionally in the production line for welding two different rough car bodies.
In the motor vehicle industry there is a growing desire to produce more than two different vehicle models one behind the other with minimum difficulty in changing over. However, this presents difficulties in the use of the clamping device disclosed by the said DE 195 33 389 A1, because an arrangement of more than two different clamping devices one behind the other usually is impossible for lack of space and would lead to undesirably great time losses in carrying the rough bodies from one clamping device to the other. Changing the clamping devices necessarily involves a long halt of the production line, because changing over is impossible without a simultaneous dismounting of the transport device around which the clamping device passes.
The invention is addressed to the problem of designing a clamping device of the kind referred to above such that a very quick adaptation to different models of rough car body will be possible. Furthermore, a production line with such a clamping device is to be created which will permit a very quick changeover between different rough car body types.
The first-mentioned problem is solved by the invention in that on both sides of the transport apparatus, ways are provided on a common base frame underneath the transport apparatus for each side carriage which can travel separately on one side of the transport apparatus, that the side carriage carries only the side members of one side of the transport apparatus, and that clamping means are provided for joining the side carriages with the base frame.
By this separation, according to the invention, of the side members and thus also of the clamps of the two sides of the production line, it is possible without disassembling the transport apparatus of the production line to remove from the production line the side carriages with the particular side members and clamps and replace them with side carriages with other hangers whenever the rough car body that is to be welded changes and therefore has to be clamped differently. Since the two ways of the side carriages are on a common base frame and the side carriages are to be joined by clamping means to the particular roller support and thus also to the base frame, then in the operation of the clamping device according to the invention, a continuous frame surrounding the rough car body is formed, precisely as in the known apparatus forming one unit, so that great rigidity and therefore great production accuracy results.
The ways can be configured variously. Components that have proven to be good for this purpose in production lines can be used if the ways are formed by roller holders with rollers journaled for rotation, on which the side carriage with a supporting frame rests.
The clamping means are intended to produce a frictional connection between the base frame and the side carriages. This can be achieved in an especially simple manner if, according to another embodiment of the invention, the clamping means are arranged on both sides of the roller support and are designed to grip the supporting frame within the roller holder.
To introduce a rough car body into the clamping device according to the invention, the latter can be moved with little effort to an open position in which the clamps are at a sufficient distance from the rough car body, if according to another embodiment of the invention the side members with the particular crossbeam are joined to the supporting frame for rotation outwardly away from the production line about an axis running horizontally parallel to the production line.
When the side carriages are exchanged, all of the clamps are simultaneously exchanged if, according to another embodiment of the invention, the side carriages have all of the clamps for the rough car body, including the bottom clamps.
The second problem mentioned, namely the creation of a production line with the clamping device described above, is solved by the invention in that on each side of the production line at least one station is provided for an additional side carriage of a pair of side carriages for an additional variant car body and if the production line has means for exchanging the side carriages. Such a production line permits the exchange of a complete clamping device by moving the two side carriages without the need to separate the transporting apparatus from the production line. Therefore such a changeover can be made very quickly, so that different models of the rough car bodies can be made quickly one after the other on a single production line.
With a production line according to the invention, by making use of the space available alongside the production line, a great number of different models of rough car bodies can be worked on without having the welding robots interfere with the exchanging of the side carriages, if before and behind a welding station of the production line several stations are provided side by side across the production line, each for one side carriage, and if for the exchange of side carriages on each side of the production line a transport path runs behind the welding station from the stations preceding the welding station to the stations following the welding station.
From each side of the production line welding robots can travel to a point directly in front of the rough car body without thereby blocking the path of the side carriages, if according to another embodiment of the invention one welding robot of one side of the production line is designed to enter into the path of the side carriages along the production line between the roller supports.